U.S. Pat. No. 5,489,259 to Jacobs et al. relates to a pressure-normalizing single-chambered static pressure device for supporting and protecting a body extremity, in particular a heel. That device has an inflatable member, a plurality of seams, and apertures along those seams. Those plurality of seams, according to Jacobs et al., "enhance the ability of that device to produce a cradling effect whereby [the] interior surface [of that device] can better engage and fully conform to the contour of the lower extremity." Col 7, lines 6-9 (brackets added for clarity and deleted numbers.) Thus, without those seams that device, according to Jacobs et al., would not adequately cradle the extremity.
A problem with the device disclosed by Jacobs et al. are that it can be easily over-inflated or under-inflated. For example, if the device is properly filled when the outer atmosphere temperature and/or barometric pressure is at level A and these atmospheric events decrease to level A-1, which is lower than A, later that day, the device will appear under-inflated. And if the device appears "under-inflated," the device fails to provide adequate support. And if the user notices the device is under-inflated, which it is not, when the atmospheric events revert to level A and the user inflates the device to appear when it was at level A, the resulting device will be over-inflated when the outer atmospheric temperature returns to level A. An over-inflated device provides too much pressure and can be deleterious to the body extremity.
The present invention solves these problems.